This post on NRO includes a reader comment:
Mr. Chait’s problem is that he doesn’t think like a businessman. The goal isn’t to maximize profits. The goal is to maximize return on investment and minimize risk.
Exactly. You don’t have to be a supply-side economist to understand this.
The question isn’t whether people can still make money with a greater tax burden. The question is whether they will find better things to do with their money. That is, will they put it to work by investing it, or will they not, by spending it on leisure activities.